1. Field of the Invention
The present invention relates to a fuel cell system, and more particularly to a fuel cell system having a plurality of fuel cells stacked to form a cell assembly, with several types of partition members separating the fuel cells.
2. Description of the Related Art
A conventional fuel cell system as noted above is shown in FIG. 26. This fuel cell system includes pairs of first opposed elongate partition members 21 and pairs of second opposed elongate partition members 22 stacked alternately in parallel crosses. With each cell C, opposite sides defining openings of intracellular passages p 1 are disposed above the first partition members 21, while opposite sides having no such openings are flanked by the second partition members 22. This arrangement is repeated to form a cell assembly NC including a plurality of rectangular plate-like cells C stacked in a spaced relationship. An intercellular passage p2 is defined between an adjacent pair of cells C. The intracellular passages p1 and intercellular passages p2 are partitioned from each other in gastight condition by tight contact between cells C and first partition members 21 and between cells C and second partition members 22.
Gas passage defining members 11 are connected to the four sides of the cell assembly NC, respectively. Each gas passage defining member 11 is box-shaped, for example, with one opening side thereof connected to one side of the cell assembly NC. The pair of gas passage defining members 11 connected in communication with the intracellular passages p1 provide an oxygen-containing gas supply passage Ks and an oxygen-containing gas exhaust passage Hs, respectively. The pair of gas passage defining members 11 connected in communication with the intercellular passages p2 provide a fuel gas supply passage Kf and a fuel gas exhaust passage Hf, respectively. However, the above known fuel cell system has a problem concerning the connection between the sides of the cell assembly NC and the gas passage defining members 11. One side surface of the cell assembly NC, for example, is defined by side surfaces 21B of the first partition members 21 and end faces 22A of the second partition members 22. This side surface of the cell assembly NC tends to be uneven because of dimensional errors in the partition members 21 and 22. It is therefore necessary to provide very complicated sealing structures in positions of connection between the gas passage defining member 11 and the side surface of the cell assembly NC. Alternatively, the partition members 21 and 22 and the like must be finished with increased precision. This in turn increases manufacturing cost, to render the system impracticable.